Two-Component Structural Adhesive Mixing for High Lap Shear Strength
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Solution Overview
Problem
Existing coatings for metal substrates lack sufficient corrosion resistance and paint adhesion, particularly in structural adhesive compositions, and there is a need for improved methods to enhance the lap shear strength and displacement of two-component adhesives.
Innovation Solution
A system comprising a deoxidizing composition with a pH of 1.0 to 3.0, containing Group IVA and/or Group IVB metals and free fluoride, followed by a coating composition with an epoxy-containing compound, diamine or polyamine with a cyclic ring, and elastomeric particles, specifically a styrene butadiene core, to treat metal substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If two-component structural adhesives are used to improve lap shear strength, then bond strength increases, but mixing ratio control becomes difficult and voids form
Solution Approach 1:
The adhesive system is segmented into two separate cartridges (first cartridge containing first component, second cartridge containing second component) that are delivered through a single dispensing tip. This segmentation allows independent control of each component while maintaining precise mixing at the point of application, resolving the contradiction between achieving high bond strength and maintaining mixing precision.
Solution Approach 2:
A mixing tip or mixing chamber acts as an intermediary between the two component cartridges and the substrate. This intermediary device ensures proper mixing of the two components in controlled proportions while preventing void formation, thereby maintaining both high lap shear strength and manufacturing precision.
2Strength
If two-component structural adhesives are used to improve lap shear strength, then bond strength increases, but air entrapment and voids increase
Solution Approach 1:
The adhesive components are pre-loaded into separate cartridges under controlled conditions, and the dispensing system is designed to maintain continuous flow without air pockets. This preliminary preparation prevents air entrapment before the bonding process begins, allowing high bond strength to be achieved without void formation.
Solution Approach 2:
The manual mixing process is replaced with a mechanically controlled pumping and dispensing system that automatically regulates the flow of both components. This mechanical substitution ensures consistent mixing ratios and eliminates air bubbles that would otherwise be introduced by manual handling, maintaining both strength and eliminating harmful voids.
3Manufacturing precision
If separate dispensing of adhesive components is implemented, then mixing ratio control improves, but dispensing system complexity increases
Solution Approach 1:
While the adhesive components are dispensed separately from two cartridges, the dispensing tips are merged into a single integrated tip assembly that combines both material streams. This merging approach maintains precise mixing ratio control while minimizing system complexity by using a unified dispensing interface rather than separate application points.
Solution Approach 2:
The dispensing system is designed with multi-functionality, where a single dispensing tip assembly handles both component delivery and mixing functions. This universal design reduces the number of separate components needed, maintaining manufacturing precision while reducing overall system complexity compared to fully separate dispensing systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system significantly enhances the lap shear strength of structural adhesives to at least 20.0 MPa, providing improved corrosion resistance and paint adhesion, forming a durable bond with metal substrates.
Implementation Method 1
a first component and a second component are delivered through a single dispensing tip in a controlled ratio to form a mixed adhesive
Implementation Method 2
Systems and methods for improved lap shear strength and displacement of two-component structural adhesives
Data Source
AI summary
Disclosed are systems for treating a substrate comprising a deoxidizing composition and a coating composition. The deoxidizing composition comprises a Group IVA metal and/or a Group IVB metal and free fluoride, optionally may comprise a homopolymer or copolymer comprising a phosphorous-containing monomeric subunit, and has a pH of 1.0 to 3.0. The coating composition comprises first and second components and elastomeric particles. The first component comprises an epoxy-containing compound. The second component comprises a diamine and/or a polyamine comprising a cyclic ring. The diamine may chemically react with the epoxy-containing compound. The present invention is also directed to methods of making the compositions, methods of coating a substrate, and coated substrates.